| Popis: |
N-Salicylideneglycinatocopper(II) complexes of the composition Cu(salgly)(L)(H2O)x with L = imidazole, x = O (I); L = 2-propylimidazole, x = 1, (II); L = pyridine, x = O (III); L = pyrazole x = 1 (IV) and L = 3,5-dimethylpyrazole, x = 1 (V) were synthesized, The EPR and ligand field specra of these compounds as well as of N-salicylideneglycinatothioureacopper(II) (IV) give evidence for a square-pyramidal Cu(II) coordination. The EPR spectra of I, II, and III can be reasonably interpreted using axial molecular g tensors, whereas the molecular g tensors of IV, V and VI exhibit orthorthombic symmetry. The experimental EPR spectrum of VI shows molecular g values in accordance with the ferrodistortive order found previously by X-ray structure analysis. In V no exchange interactions between crystallographically nonequivalent Cu(II) ions were found. The complexes I–IV show exchange coupled g parameters, corresponding to an antiferrodistortive (I, III) or disturbed antiferrodistortive ordering (II, IV). The alkyl-substitution on the neutral ligand and the presence of water in the crystal structure strongly influence the exchange interactions between Cu(II) ions. |
